Welded steel boiler



Feb. 28, 1956 F. SMITH 2,736,298

WELDED STEEL BOILER Filed July 25, 1952 3 SheetsSheet 1 fizz/81%;: EMJae 2 7V 9 M 5% 5 ham/ 9W Feb. 28, 1956 F. SMITH WELDED STEEL BOILER 3Sheets-Sheet 2 Filed July 25, 1952 Jzmfi: 17'012/9 @yzfi/ 9 w 4' r j W WF T T Feb. 28, 1956 F. SMITH 2,136,2

WELDED STEEL BOILER Filed July 25. 1952 3 Sheets-Sheet 3 Unit Thisinvention relates to boilers or hot water heaters, and a primary objectof the invention is to provide a heater or boiler, primarily fordomestic heating purposes, of generally improved characteristics. Theterm -boilerwill be understood to include water heating units of thecharacters used with the several types of domestic heating systems suchas steam, hot water, vapor, and the like.

More specifically, the invention has for an object the provision of aboiler of simple and economical construction, having an inherently highfunctional efliciency and an extremely low cost of maintenance.

Another object of the invention is to provide a boiler which by reasonof certain novel design features will exhibit economy both ofconstruction and operation.

Still another object of the invention is to provide a fabricated steelboiler affording exceptionally high econorny of that material.

To this latter end, the invention contemplates provision of boiler ofthe water tube type wherein the combustion and heat exchange chambersare encased by non-metallic refractory walls, said walls beinginexpensive and durable and functioning both to conserve heat and fueland to minimize operating noises of the furnace.

A further object of the invention is to provide an oil firedboilerwherein the boiler noises and the noises generated by the oil burner arereduced to a practical minimum.

Still another object of the invention is to provide a boiler of thestated type wherein ready access is afforded for cleaning and repairpurposes and for installation and removal of the refractory elements ofthe combustion chamber.

A further object of the invention is to provide a welded steel watertube boiler wherein by reason of novel design access is afforded to allwelded joints of the structure for inspection and possible repair.

Still another object of the invention is to provide an Oil fired watertube boiler wherein access may be had to the combustion chamber withoutdismounting the oil burner unit.

Still another object of the invention is to provide a boiler of thestated character employing refractory side panels and provided withsimple and practical means for mounting said panels in the boilerstructure.

Another object of the invention is to provide a novel refractory wallpanel for boilers of the stated type.

The invention resides also in certain other novel structural detailshereinafter described and illustrated in the attached drawings, wherein:

Figure 1 is a vertical sectional view of a boiler made in accordancewith the invention;

' Figure 2 is a front elevational view of the boiler with the burnerunit and easing removed, as reviewed from the line 22, Figure 1;

Figure 3 is a sectional view on the line 3-3, Figure 1;

Figure 4 is a sectional view on the line 4-14, Figure 1;

Figure is a view in perspective. of the boiler unit with States Patent 0aside panel displaced and a portionof the front panel broken away toshow the details of construction; and

Figure 6 is a fragmentary elevational and partial sectional view of oneof the refractory side wall panels.

As previously stated, the boiler is of the water-tube type and isfabricated from steel plate by welding. The body of the boiler comprisestwo flat tube plates 1 and 2 in the apertures of which the ends of tubes3 are secured by welding or if preferred by expansion. The boilercomprises also a lower shallow U-shaped member 4 which is secured bywelding to the underside of the lower tube plate 2; and the respectiveopenends of this member 4 are closed by flat substantially rectangularplates 5 and 6'which are secured at their upper edges by welding to theunderside of the lower tube plate 2 and also the end edges of the member4. A sealed chamber is thus formed between the member 4 and the lowertube plate with which the lower ends of the tubes 3 are incommunication.

In the present instance the plates 5 and 6 extend below the bottom ofthe member 4 (see Figure 3) so as to-form a support for the boiler,thebottom of the member 4 being thus elevated abovethe underlyingsupporting or floor surface. It is preferred also to provide reinforcingor staying members 7 and 8 (see Fig. 1) in the form of stays which aresecured by welding to the'inner lower surface of the member 4 and totheunderside of the lower tube plate 2.

The boiler body also comprises an inverted U-shaped or dome-like member11 of relatively great depth which seats upon the upper surface of theupper tube plate- 1 and is secured by welding tothe latter. Flat endplates 12 and 13, secured by welding to the upper surface of the plate 1and to the respective end edges of the member 11, form with the latter asealed chamber at the top of the plate 1 which is in communication withthe upper ends of the tubes 3. Ifdesired, a strut member 14, welded atits ends to the upper surface of the tube plate 1 and to the innersurface of the plate 13, extends diagonally between these plates toafford reinforcement for the plates 1 and 13 against distortion due topressure.

Plate 12 may be likewise strengthened.

A preferred arrangement of the tubes 3 is best illustrated in Figure 4.As shown in that figure as well as in the other figures, the tubes arearranged in abank of transverse rows at one end of the above describedstructure, which end constitutes the back of the combustion or heatexchange chamber of the boiler. The tubes also extend forwardly alongthesides' of the chamber and across the front so as to leave an openspace in the forward part of the structureforreception of the elementsof the hearth or fire box hereinafter described. The tubes are spaced soas. to provide a central opening 22 at the front of the boiler throughwhich the flame from a burner 20 may be projected into the combustionchamber; and a gap 23 is also provided at one side be-. tween the tubesto afford access to the interior of the structure for purposeshereinafter set forth.

It will be noted that the tubes are spaced inwardly from both the side,front, and rear edges of the upper and lower tube plates 1 and 2, thusaffording fiat shelfli ke extensions at the edges of the plates formounting side panels 24 and 25 and front and rearpanels 26 and 27. Thesepanels fit closely between the confronting edge portions of the tubeplates and enclose the tubes. The panels in effect constitute the sidewalls of the combustion chamber of the boiler and the structure of thesepanels, which constitute an important element, of the invention, will behereinafter described.

It will be noted by reference to Fig. 4 that in the present instance theside panels 24and 25 and the front panel 26 seat against the sides ofthe adjoining tubes 3,

whereas the rear panel 27 is spaced rearwardly from the rear row of thetubes by abutment strips 30 on the tube plates. If desired, the side andfront panels may be spaced by similar means from the tubes which theyrespectively confront. As illustrated, the panel 26 is provided with anopening 28 for reception of the tubular end of the burner 20, shown inFig. 1; and the rear panel 27 is provided with an opening 31 forreception of a flue pipe 32.

It will be noted also by reference particularly to Figs. 1, 3 and 5 thatthe member 11 is inset from the edges of the upper tube plate 1. The endplates 12 and 13 while extending the full width of the tube plate 1 arespaced inwardly from the front and rear edges of the latter. Theprojecting edge portions of the tube plate provide support for suitableinsulation encasing the dome 1.1 as indicated by the reference numerals33, 34 and 35 in Figs. 1 and 3.

Located within the forward part of the combustion chamber of the boilerin the tubeless area is a fire box or hearth structure designatedgenerally by the reference numeral 36. This fire box, into which theflame of the burner 29 is projected, is composed of suitable highrefractory material and consists in the present instance of a base orfloor slab 37 which rests upon the lower tube plate 2, side slabs 38 and39, respectively, the lower edges of which also seat upon the tube plate2, and a rear wall slab 41, the lower edge of which seats upon the tubeplate 2 and which is of the same height as the side slabs 38 and 39. Theslabs 37, 38, 39 and 41 are in engagement with each other to form atight open-top box, the forward wall of which is formed by the frontpanel 26 of the combustion chamber. In the present instance a refractorycross-member 42 is provided at the top of the rear wall which overhangsthe back of the fire box to aiford a desirable corbelling effect asillustrated in Fig. 1.

As also illustrated in Fig. l and in Fig. 5, the rear slab 41 is fittedbetween adjoining pairs of the tubes 3 at each side of the boiler and isthereby supported securely in the upright position. This slab may bereadily inserted between the supporting tubes and may readily bewithdrawn after removal of one of the side panels 24 and 25. Sidewisedisplacement of the slab 41 is prevented by the last named panels. Theside slabs 38 and 39 bear against the inner sides of the tubes which lieat the opposite sides of the combustion chamber and find support againstthese tubes. The fioor slab 37 fits closely between the side slabs 38and 39 and thereby in effect locks the side slabs in the uprightpositions; Forward displacement of the side slabs 38 and 39 is preventedby engagement of the forward edges thereof with the front panel 26 ofthe furnace structure. It will be noted also that the forward edgeportions of the side slabs 38 and 39 are fitted between adjoining pairsof the tubes 3 at the forward end of the boiler structure so that theslabs are positively supported in the upright positions. The transversemember 42 rests upon the upper edge of the rear slab 41 and upon theupper edges and rear portions of the slabs 38 and 39 and is confined atthe ends between two of the tubes 3 disposed at opposite sidesrespectively of the combustion chamber. The elements of this fire box orhearth structure may be further united by suitable cement if desired. Itwill be apparent that these elements are readily accessible forinspection, cleaning and repair after removal of the side panel 25through the space 23 between the spaced tubes referred to above. Removalof the side slabs may be effected also from the front by removal of thefront panel 26.

The structural elements of the hearth structure described above arepreferably composed on a suitable high temperature refractorycomposition, such compositions being well known and readily available inthe art.

The side, front and rear panels 24, 25, 26 and 27 do not require amaterial of the same high service temperature as the'hearth structureelements described above.

These .panels are relatively remote from the flameof the burner 20 andare shielded to a degree by the interposed water tubes 3. The sidepanels have an important functional purpose however and are required tohave a composition capable of withstanding substantially higher thanatmospheric temperatures over an extended period of time withoutmaterial loss of inherent strength and insulating properties. We havefound it of advantage to form these panels of an integral body ofmaterial consisting of an outer layer 43 of Portland cement and anaggregate such as expanded shale affording a relatively strong and rigidstructure, and an inner layer 44 of a refractory material of higherservice temperature but lesser inherent strength composed, for example,of a mixture of Portland or other cement and a light weight heatresisting aggregate such as perlite or vermiculite. The two layerssimultaneously cast unite to form an integral body having the desiredstrength and rigidity conferred by the outer layer 43 and the thermalresistance characteristic of the refractory inner layer 44. The twolayers having substantially the same coefficient of expansion, do nottend to separate and the composite structure exhibits a substantialfreedom from internal stresses of a character tending to crack orfracture the panel.

The front and rear panels 26 and 27 may beheld in place by means offlanges 45, 45 and 46, 46 on the front and rear edges respectively oftube plates 1 and 2. The flanges are welded to the plates and the panelsmay he slid into place edgewise behind these retaining flanges. Thepanels 24 and 25 may be held in place by clamps of the characterillustrated at 47 and 43 in Figure 2, said clamps consisting of an anglewelded to the plate 1 or 2, as the case may be, a bolt or stud 49passing through the angle, and a clamping angle bar 51 secured by saidbolt at the outer face of the panel. There may be two or more of theseclamps at each side of the boiler, and they may be readily released byremoval of the studs 49, 49 for removal of the panel when required.Obviously, the panels may be of sectional form, if desired, forconvenience of handling.

In producing the metal body of the boiler, the ends of the tubes arefirst welded in the tube plates at the top of the upper plate and bottomof the lower plate respectively, the plates having been drilled orpunched with the necessary tube holes. The member 4 may then be weldedat its edges to the underside of the lower tube plate, and the endplates 5 and 6 then welded to the tube plate and to the ends of member4. Prior to the latter operation the stays 7 and 8 may be welded to thetube plate 2 and the member 4. The member 11 is now welded at its loweredges to the upper surface of the upper tube plate 1, and thereafter thefront plate 13 is welded to the tube plate and to the forward edges ofthe member 11. After the strut 14 is attached to the inner face of theplate 13 and to the tube plate 1, the back plate 12 may be welded to thetube plate and to the rear edge of the member 11 to complete theassembly.

It will be noted that the front plate 13 is provided With opening 52 and53 for reception of fittings 54 and 55 for the inlet and outlet pipes 56and 57 of the external heating system; and openings 58, 59 and 61 arealso provided for the required instruments such as the pressure andtemperature gauge 62, and aquastats 63 and 64. If provision is to bemade for domestic hot water supply from the boiler, means (not shown)will be provided either in the front plate 13 or rear plate 12 forsupporting a suitable coil within the chamber 65 formed by the member 11and to connect this coil to the domestic Water system. The outlet port53 is located in a position below the top of the member 11 so as toafford an air space 66 in the chamber 65 above the level of the water inthe latter. This space functions, in the case of the hot water systemillustrated, as an expansion chamber in lieu of the separate chamberconventionally employed.

The mode of operation of the boiler described above will be apparent tothose familiar with the art. As previously indicated, the constructionaffords valuable characteristics not found in the more conventionalboilers of the same class. Among these characteristics are the extremeaccessibility for inspection of all welded joints, it being noted thatall such joints, including those where the tubes pass through the tubeplates, are immediately accessible for rewelding or for repair of leaks;accessibility also for cleaning all combustion chamber surfaces and forinspection, repair and replacement of the elements of the hearthstructure by simple removal of one or more of the wall panels;accessibility for all of these purposes without disa-ssembly ordemounting of the burner unit; simplicity of fabrication of the metallicbody of the boiler utilizing a minimum number of steel elements ofsimple readily producible shapes and the substantial exclusion of insidewelds; the use of refractory non-metallic wall panels which reducesmaterially the weight of metal in the boiler as a whole and which, byreason of the high sound insulating properties of the panels, reducesthe operating noise level to a minimum; the excellent thermalconservation characteristics resulting from the use of the refractorywall panels and the effective insulation of the hot surfaces of theboiler; and the relatively high efficiency arising from the large areaof the heat transfer surfaces exposed to the hot combustion gases andthe use of both radiation and conduction (by way of the incandescentwalls of the hearth structure in contact with the tubes).

While the boiler structure described above constitutes a complete andself-sustained operating unit, it is preferable to encase the saidstructure and the burner unit in a suitable casing as shown at 67 inFigs. 1 and 4.

I claim:

1. In a welded steel boiler, a metallic structure comprising upper andlower tube plates and a plurality of tubes extending between said platesand having their ends welded in apertures in the latter, a substantiallyU-shaped plate member welded along its straight edges to the uppersurface of the said upper tube plate, a second U-shaped plate memberwelded along its straight edges to the lower surface of the lower tubeplate, and an end plate Welded to each end of each of said U-shapedmembers and to the proximate surfaces of the upper and lower tube platesand forming with said U-shaped plate members enclosed header chamberscommunicating respectively with the upper and lower ends of said tubes,the edge portions of the upper and lower tube plates extending beyondthe welded edges of the respective associated U-shaped member and endplates to provide unobstructed perimetral areas on the tube plates, andwall panels fitted between said edge portions and forming the side wallsof an encltgsed chamber between the tube plates traversed by said tu es.

.2. A tubular boiler consisting of a unitary metallic structurecomprising confronting upper and lower tube plates and tubes connectingsaid plates and confined to areas of the latter spaced from theperimetral edges thereof, a plurality of pre-formed complementary wallpanels of non-metallic refractory material removably supported betweenthe perimetral edge portions of said tube plates and forming with thelatter an enclosed combustion chamber embracing the said tubes, thetubes being arranged in rows at each side and at the front of saidstructure and in a plurality of transverse rows at the back of thestructure and thereby affording an unobstructed space between saidplates toward the front of the structure, and fire box elementssupported by the tubes within said space.

3. A boiler according to claim 2 wherein the fire box structurecomprises a refractory slab seated upon the lower tube plate togetherwith side and rear refractory slabs having their lower edges seated onthe said lower tube plate, each of said slabs having at least one endthereof confined between adjoining tubes and being thereby positivelyretained in the upright position.

4. A boiler according to claim 3 wherein the series of tubes at one sideof the combustion chamber are interrupted to afford an access openingfor installation of the elements of the fire box structure.

5. A boiler consisting of a unitary metallic structure comprisingconfronting upper and lower tube plates and tubes connecting said platesand confined to areas of the latter spaced from the perimetral edgesthereof, a plurality of pre-formed complementary wall panels ofnon-metallic refractory material removably supported between theperimetral edge portions of said tube plates and forming with the latteran enclosed combustion chamber embracing the said tubes, including ahearth structure consisting of refractory elements having thermalcontact with certain of said tubes.

6. A tubular boiler consisting of a unitary metallic structurecomprising confronting upper and lower tube plates and tubes connectingsaid plates and confined to areas of the latter spaced from theperimetral edges thereof, a plurality of pre-formed complementary wallpanels of nonmetallic refractory material removably supported betweenthe perimetral edge portions of said tube plates and forming with thelatter an enclosed combustion chamber embracing the said tubes, metallicmembers secured to the upper surface of the upper tube plate and to thelower surface of the lower tube plate and forming header chamberscommunicating with the ends of the tubes, said tubes being arranged toafiord a space at one end of said chamber unobstructed by the tubes, anda refractory fire box structure within said space.

References Cited in the file of this patent UNITED STATES PATENTS323,957 Pearce Aug. 11, 1885 696,714 Burgher et a1. Apr. 1, 19022,117,511 Scott May 17, 1938 2,195,274 Ferguson Mar. 26, 1940 2,305,847Digby Dec. 22, 1942 2,327,750 Turner Aug. 24, 1943 2,362,107 Wallis eta1. Nov. 7, 1944 2,607,325 Denker et al Aug. 19, 1952 FOREIGN PATENTS575,083 Great Britain Feb. 1, 1946

